Submission #448537

#	Time	Username	Problem	Language	Result	Execution time	Memory
448537		Tenis0206	Rack (eJOI19_rack)	C++11	100 / 100	1 ms	312 KiB

rack

#include <bits/stdc++.h>

using namespace std;
const int Mod = 1e9+7;
long long lgput(int b, int e)
{
    long long p=1;
    while(e)
    {
        if(e%2==1)
        {
            e--;
            p=(1LL*p*b)%Mod;
        }
        else
        {
            e/=2;
            b=(1LL*b*b)%Mod;
        }
    }
    return p;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    long long n,k;
    cin>>n>>k;
    long long rez=1;
    while(k!=1)
    {
        --n;
        if(k%2==0)
        {
            rez+=lgput(2,n);
            rez%=Mod;
        }
        k=(k+1)/2;
    }
    cout<<rez<<'\n';
    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60